Sound director



W. S. DICKSON SOUND DIRECTOR Filed Feb. 17, 1926 2 Sheets-Sheet 1 Nov. 1,1927. 5 1,647,439

Walier. l7 iclison Nov. 1, 1927.

W. DICKSON scum; DIRECTOR Filed Feb. 17, 1926 2 Sheets-Sheet 2 Mahayana Patented Nov. 1, 1927.

WALTER S. DIQKSON, OF MILWAUKEE, WISCONSIN.

SOUND DIRECTOR.

Application filed February 17, 1926. Serial No. 88,857.

Myinvention is a means for directing sound and is to be used in connection with telephone transmitters, phonograph recording instruments and radio microphones, in the trarsmission, recording and broadcasting of sound. The invention includes the provision 1n means for directing sound, of sound exhausts of sufficient number as may be required and of various mechanicalconstruction, and have as their purpose the prevention of the reaction of sound vibrations, in their rebound from the transmitting, recording or broadcasting diaphragms.

By this means sound or sound vibrations from the point or moment of their creation, are directed through the chamber of this device, towards the transmitting, recording or broadcasting apparatus.

To this end theinvention includes a chamber which may vary in form and shape from spherical or ovoidal shapes, to the form of double truncated cones of equal or unequal angles or length that are joined at the base. I Sound exhausts may be in the form 'of openings or slots in the walls of the device, located at or near its outlet, or at or near its point of Widest diameter or both, or at any point within the wallsthat experiment may determine, and may even be constructed so as to make a complete or partial separation of the walls of the chamber into two or more sections. Sound exhausts not only prevent the reactions of sound vibrations in their rebound from the transmitting, recording or broadcasting microphones or apparatus, thereby eliminating false overtones in the recorded or transmitted sound, but effectively break theair cushion within the chamber of the device, which interferes with perfect conduction.

I have illustrated in the accompanying drawings diagrammatic forms of the inven tion in which Figure l is a sectional elevation of a telephone mouth-piece constructed according to my invention.

Fig. 2 is a like view of a modified form of mouthpiece.

Fig. 3 is a like view of another modification.

Fig. 4. is a like view of another modificas tion.

I Fig. 5 is a like view of another modifica tion.

stances, have been t,Fig. 6 is a like view of another modificaion. I.

F ig. 7 is a diagrammatic view, partly in section, of an individual recording horn embodying my invention. v t Fig. 8 is a like View of a recording laboraory. V

Fig. 9 is an enlarged view of the pivoted shutters used in the recording laboratory of Fig. 8. r .In these drawings I have shown the directmg device to consist of a shell 10 as of two truncated cones with their large bases adjacent but spaced apart to allow for sound exhausts 11. Obviously such exhausts may extend either partially around the periphery of the shell or completely so. A screw threaded portion '12 is provided tosecure the device to the ordinary telephone transmitter.

'The same principle is followed in constructing the devices of Figs. 2 to 8, except that slight modifications of shape are utilized. These variations under certain circumfound to be advantageous.

In Fig. 7 the shell of the device has been shown to be provided with a mouthpiece 13 for individual recording on the recording machine 14.

In Fig. 8 a laboratory has been constructed on the same principle, large enough to accommodate a band or orchestra. In this case additional exhausts 15 are provided, as shown.

Present methods of transmission, recording and broadcasting sound, permitsound vibrations to occur in every direction from the point of their creation and but segments of these spherical vibrations act upon the transmitting, recording or broadcasting dia-v phragms or apparatus.

By this device sound vibrations from the moment of their creation, are directed for- Ward and are permitted toexpand only' within the confines of the device, to the point of its greatest diameter which is its point of greatest amplification and from there they are modified by the reducing form of the walls of the device in their transmission, to the transmitting, recording or broadcasting diaphragms or apparatus.

This sound director, when applied to telephone transmission, is substituted for the mouthpiece of the transmitter. It may be spoken into directly, or the mouth may be ing held at a distance, up to six inches from the device, without losing its efficiency. When spoken into directly, the lightest whispered conversation is perfectly transmitted and clearly audible to the person receiving the message.

In its application to phonograph recording and radio broadcasting, the sound direc tor may be either a small device constructed to receive and transmit sound, or it may be constructed in the form of a chamber, large enough at one end to contain a band or orchestra, in which the sound is amplified to the point of the widest diameter of the chamber, and from there modified by the reducing diameter of the walls in their continuation to the recording diaphragms or apparatus, or broadcasting microphones.

A sound exhaust as close as possible to the recording or transmitting diaphragm or apparatus to exhaust the greater partot the recorded sound at or close to the point of record is absolutely necessary in a device where sound is confined in its transmission to recording or transmitting apparatus.

Of nearly equal importance is the sound exhaust at or near the widest point of the shell of the ogival or double conical sound directing device. This exhaust effectively breaks the air cushion within the chamber and permits the circulation of the air with in it and the 'free forward movement 0t sound waves to and beyond the point of their greatest amplification, to the pointot record.

Sound exhausts the volume and intensity of sound being recorded or transmitted may demand but for Hit ximum efliciency must be constructed with their openings in line with the angle or sound deflection from the recording or transmitting apparatus. Vhether in either section of the directing chamber they must lead diagonally through 'the walls of the chamber towards the recording point of sound in order to accept and transmitting apparatus in direct line of their rebound or deflection, the recorded sound waves.

In this construction of sound exhausts the inner edge overlaps the outer edge and in eifect makes the wall of the chamber continuous so as to offer no escape or ellectivebrealr to sound as it passes forward to the recordor transn'iitting apparatus.

Sound exhausts although they may be constructed as to make a complete separation may be of any number as xhaust from the recording or.

of the director into two or more parts will generally be formed as a series of slots cut diagonally through the shell of the director towards the recording point. This series of cuts will be made around the circumference of the shell at any distance from the recording apparatus.

It is also vitally important that the shape or shapes of the sound director, not only direct sound waves forward, but permit 01 their amplification in the ratio of their ultimate reduction, in order to produce an efficient device.

Having thus described my invention, what I claim is:

1. The combination with an instrument for the recording or transmission of sound, of a shell having reducedends and an enlarged center, one end being adapted for connection with the instrument and the other adapted to receive the full sound to be recorded so as to confine the sound to the shell, the construction being such as to first allow the sound waves created to enlarge, and then gradually reduce them as they pass to the instrument, and ports in the wall of said shell through which sound may be exhausted.

2. F or use in combination with an instrument forv recording or transmitting sound, a shell having an enlarged center and reduced ends, the sound being created in one of the reduced ends, and passing out of the opposite. end which is placed in proximity to a recording or transmitting instrument, the enlarged central section permitting the enlar ement of the sound waves, and a reduced end the subsequent gradual reduction thereof, and ports in the wall of said shell through which sound may be exhausted.

3.111 combination, an instrument for the recording or transmission of sound, means within which to confine sound from its point oit' creation to the instrument, said means being spaced apart "from the instrument, and ports in the wall of said shell through which sound. may be exhausted.

LFor use in combination with an instrument or a aparatus for recording or transmitting sound, a shell having an enlarged center and reduced ends having a number of openings covered by pivoted shutters to be used to exhaust sound already recorded or transmitted and prevent its recurrence in the recording oi new sound.

In testimony whereof, I affix my signature.

WALTER S. DICKSON. 

